Acylthiomethyl esters of cephalosporins

ABSTRACT

New acylthiomethyl esters of cephalosporins have the formula   WHEREIN R1 is thienylmethyl or thienylmethyl bearing on the carbon of the methyl group a hydroxy, carboxy, amino or ureido group; R2 is hydrogen or lower alkyl; R3 is lower alkyl; and X is hydrogen, lower alkanoyloxy, lower alkylthio, thiadiazolylthio, (lower alkyl)thiadiazolylthio, tetrazolylthio or (lower alkyl)tetrazolylthio. They are useful as antibacterial agents.

United States Patent 1191 Breuer 1 Dec. 16, 1975 ACYLTHIOMETHYL ESTERS OF CEPHALOSPORINS [75] Inventor: Hermann Breuer, Regensburg,

Germany [73] Assignee: E. R. Squibb & Sons, Inc.,

Princeton, NJ.

22 Filed: Nov. 25, 1974 211 Appl. No.: 527,107

Related US. Application Data Continuation-impart 'of Ser. No. 277,700, Aug. 3, 1972, Pat. No. 3,860,591, and Ser. No. 516,566, Oct.

3,852,282 12/1974 Dolfini ..260/243C Primary Examiner-Paul M. Coughlan, Jr. Attorney, Agent, or FirmLawrence S. Lcvinson: Merle J. Smith [57] ABSTRACT New acylthiomethyl esters of cephalosporins have the formula S R CONH //,--N I CHZX 1 COO-CH-S-COR3 wherein R is thienylmethyl or thienylmethyl bearing on the carbon of the methyl group a hydroxy, carboxy, amino or ureido group; R is hydrogen or lower alkyl', R is lower 'alkyl; and X is hydrogen, lower alkanoyloxy, lower alkylthio, thiadiazolylthio, (lower a1- kyl)thiadiazolylthio, tetrazolylthio or (lower alky1)tetrazolylthio. They are useful as antibacterial agents.

16 Claims, N0 Drawings ACYLTHIQMETI-IYLTESTERSYOF' 1.

CEPIIALOSPORINS This application is a continuation-impart of application Ser. No. 277,700, filedAugQ, 1972, US. Pat. No. 3,860,591, issued Jan. 14, 1975, and of application Ser. No. 516,566, filed Oct. 21, 1974.

BACKGROUND OF THE INVENTION I invention are more readily absorbed from the gastrointestinal tract and then are readily hydrolyzed to the free cephalosporin thereby providing a high concentration of antibiotically active substance.

SUMMARY OF THE INVENTION This invention relates to new acylthiomethyl esters of cephalosporins having the formula R is thienylmethyl and thienylmethyl bearing on the carbon of the methyl group (ct-carbon atom) a hydroxy, carboxy, amino or ureido group; R is hydrogen or lower alkyl. R is lower alkyl. X is hydrogen, lower alkanoyloxy, lower alkylthio or the heterocyclic substituted mercapto groups thiadiazolylthio, (lower alkyl)- thiadiazolylthio; tetrazolylthio or (lower alkyl)tetrazolylthio. I

When R is a basic substituent the products form acid addition salts which'are also within the scope of the invention.

The preferred members of the group are those wherein R is thienylmethyl and a-substituted thienylmethyl wherein thea-substituent is amino or ureido, R is hydrogen or methyl; R is methyl; and X is hydrogen,

loweralkanoyloxy, especially acetoxy or propionyloxy,

l 3,4-thiadiazolylthio, S-methyl-l ,3,-4-thiadiazol-5- yl-ylthio or 5-methyltetrazol-l-ylthio,

DETAILED DESCRIPTION OF -,THE. INVENTION The various groups represented by the symbols have the meanings defined below and these definitions are retained throughout this specification.

The lower alkyl groups are straight or branched chain hydrocarbon radicals having one to eight carbons in the chain, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, amyl or the like. The lower alkenyl groups are monounsaturated groups like those first described, the two to four carbon members being preferred.

The aryl groups are monocyclic carbocyclic aryl groups including simply substituted members. By way of illustration, this includes the phenyl ring and simply substituted phenyl containing one to three substituents (preferably only one) such as the halogens (chlorine and bromine being preferred), lower alkyl groups such as those defined above, lower alkoxy groups, (i.e., lower alkyl groups of the type defined above attached to an oxygen), hydroxy, amino, carboxy and the like. In the case of the last two named substituents there is preferably only one, especially in the para position of the phenyl. I

The aralkyl groups include a monocyclic carbocyclic aryl group attached to a lower alkyl group, both as defined above, benzyl being preferred.

The cyclo-lower alkyl groups are the alicyclics of three to six carbon atoms, e.g., cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl; cyclopentyl and cyclohexyl are preferred. The cyclo-lower alkenyl groups are the 4 to 6 carbon monounsaturated cyclic groups including cyclobutene, cyclopentene and cylcohexene. The cyclo-lower alkadiene groups are similar cyclic groups which have two double bonds, particularly cyclohexadienyl and especially l,4-cyclo hexadienyl. All of these are attached to a bridging methylene group.

The heterocyclic groups represented by R are the heterocyclic radicals thienylmethyl, furylmethyl, oxazolylmethyl, isoxazolylmethyl, oxadiazolylmethyl, thiadiazolylmethyl, tetrazolylmethyl and thiazolylmethyl, as well as these heterocyclics with the substituents halo, lower alkyl (particularly methyl and ethyl),

phenyl, and thienylmethyl having amino, hydroxy, carboxy or ureido as an oz-substituent.

In addition, the R groups, especially those with a cyclic substituent, may be substituted on the a-carbon atom. These include hydroxy, amino, carboxy, ureido, lower alkanoylureido, sulfonylureido, sulfonyl or sulfonamido.

The lower alkanoyloxy, aroyloxy and aralkanoyloxy groups represented by X include the acyl group of the acid esters. The lower alkanoylradicals are the acyl radicals of lower fatty acids containing alkyl radicals of the type described above. The lower alkanoyloxy groups include, for example, acetoxy, propionyloxy, butyryloxy and the like. The aroyloxy groups are derived from monocyclic carbocyclic groups of the kind described. Similarly the aralkanoyloxy groups consist of monocyclic carbocyclic aryl and alkanoyloxy radi cals of the type described. X also represents the radical of an amine, e.g., an alkylamine like methylamine, ethylamine, dimethylamine, triethylamine, aralkylamine like dibenzylamine, N,N-dibenzylpyridinium, pyridinium, l-quinolinium, l-picolinium, etc.

The lower alkylmercapto groups represented by X:

The compounds described above are essentially neutral, when R however, is a basic group, a-aminobenzyl for example, acid addition. salts of the conventional type are formed, e.g.,-hydrohalides like the hydrochloride, other inorganic acid salts like the sulfate, phosphate, organic salts like the citrate, benzenesulfonate, toluenesulfonate, etc.

The new compounds of this invention may be synthesized by several methods.

According to one method the carboxy group of a cephalosporin of the formula CHX 2 COOI-I (III) This reaction is effected at a temperature in the range of about C. to ambient temperature in an inert organic solvent such as tetrahydrofuran, dimethylformamide, dimethylacetamide, acetone, dioxane or the like and a product of formula I results.

Alternatively, a salt of a cephalosporin of the formula S R -CONH N CH X COOY is made to react with a compound of the formula hal-CH-S-CORa R R R and X have the same meaning as above, Y is a cation, e.g., a metal cation such as the alkali metal cations sodium and potassium, or the cation of a nitrogen base such as the ammonium ion, trialkylammonium ions, etc., and ha] is a halogen, especially chlorine or bromine.

This reaction is effected at a temperature of about 0 to 50C., preferably in a suitable inert organic solvent 65 such as dimethylformamide, dimethylacetamide, acetone, dioxane or the like.

The compounds of formulas III and V are produced by known methods [H. Bohme et al., Liebigs Annalen 623, 92-l O2 (1959)], for example, by reacting a thioacid of formula VI below with an aldehyde of formula VII below whereby the corresponding hydroxymethyl ester of the thioacid III is formed, this is halogenated, for example by treatment with a phosphorus trihalide, like phosphorus tribromide, to obtain the corresponding halomethyl ester of formula V below.

The synthesis of the new acylthiomethyl esters of cephalosporins of formula I may also be effected from a-haloalkyl esters of cephalosporanic acid derivatives of the formula (VIII) l COOCH-hal The compound of formula VIII is reacted with a salt, for example, an alkali metal salt, of a compound of formula VI above in an inert organic solvent, such as those named previously, at a temperature of about 0 to 50C., preferably at room temperature.

The compounds of formula I may also be produced by acylating a compound of the formula R CHZX 2 COOCH-S-CO-R or a salt thereof with a reactive derivative of the acid R COOH. Such derivatives include, for example,

. acid halides, acid anhydrides, mixed anhydrides of the acid with, for example, carboxylic acid monoesters,

trimethylacetic acid or benzoic acid, acid azides, active esters such as cyanomethyl ester or p-nitrophenyl ester or active amides such as acylimidazoles.

The acid R COOH may also be reacted with a compound of formula IX in the presence of a carbodiimide, for example, N,N'-dicyclohexylcarbodiimide, or an isoxazole salt such as N-ethyl-S-phenylisoxazolium- 3 -sulfonate, or 2-ethoxyl ,Z-dihydroquinoline- 1 -carboxylic acid ethyl ester.

The compounds of formula IX are also new, and may be produced, for example, by the reaction of a compound of the formula N CHZX O COOY with a compound of formula V above. This reaction is effected at a temperature within the range of about to 50C., preferably about room temperature, in an inert solvent such as dimethylformamide.

The compounds of formula IX may also be produced from compounds of formula I, especially when R is a selected substituent such as benzyl or phenoxymethyl, by converting this particular compound of formula I with phosphorus pentachloride under anhydrous conditions to an imide chloride of the formula COOCH-S CO-R Then, by treating the product of formula XI with certain alcohols, e.g., methanol or isopropanol, and further with water, the product of formula IX optimally in the form of its salt, such as the hydrochloride or tosylate, is obtained. By forming the salt the molecule is stabilized and more readily isolated.

Further process details are also provided in the illustrative' examples.

Certain of the compounds of this invention may exist in different optically active forms. The various stereoisomeric forms as well as the racemic mixtures are within the scope of the invention. 5

The compounds of this invention have antibacterial activity against both gram positive and gram negative organisms such as Staphylococcus aureus, Salmonella schottmuelleri, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli and Streptococcus pyogenes. They may be used as antibacterial agents in a prophylactic manner, e.g., in cleaning or disinfecting compositions, or otherwise to combat infections due to organisms such as those named above. They also show activity against fungi like Candida albicans. For example, a

compound of formula I or a physiologically acceptable salt thereof may be used in various animal species in an amount of about 3 to 100 mg./kg., daily, orally or parenterally, preferably orally, in single or two to four divided doses to treat infections of bacterial origin, e.g., 4.0 mg./kg. in mice.

Up to about 500 mg. of a compound of formula I or a physiologically acceptable salt thereof may be incorporated in an oral dosage form such as tablets, capsules or elixirs or in an injectable form in a sterile aqueous vehicle prepared according to conventional pharmaceutical practice.

They may also be used in cleaning or disinfecting compositions, e.g., for cleaning barns or dairy equipment, at a concentration of about 0.01 to 0.5% by weight of such compounds admixed with, suspended or dissolved in conventional inert dry or aqueous carriers for application by washing or spraying. They are also useful as nutritional supplements in animal feeds.

The following examples are illustrative of the invention. All temperatures are on the centigrade scale. Additional variations may be produced in the same manner by appropriate substitution in the starting material.

EXAMPLE 1 21.4 g. (0.05 mol.) of the potassium salt of 7- (phenylacetarnido)cephalosporanic acid, 8.45 g. (0.05 mol.) of (bromornethyl)acetylsulfide and 200 ml. of anhydrous dimethylformamide are stirred for 48 hours at room temperature with the exclusion of moisture. The reaction mixture is poured, with stirring into 1 liter of ice water, treated with ethyl acetate and the aqueous phase is shaken twice more with ethyl acetate. The combined ethylacetate extracts are washed five times with water, decolorized with activated carbon, dried with magnesium sulfate and the solvent then driven off in vacuo in a rotary evaporator. The crude yield is 21.2 g. of a viscous syrup.

The crude product is purified by dissolving in methylene chloride and the solution is chromatographed in a silica gel column. The product is eluted from the column with a mixture comprising 2 parts of methylene chloride and 1 part tetrahydrofuran. After concentrating, there are obtained 12.8 g. of residue, which solidifies upon trituration with ether. The product thus obtained, the acetylthio)methyl ester of 7- (phenylacetamido)cephalosporanic acid, melts at -l00.

The following additional products are made by the procedure of Example 1 by substituting for the bromomethylsulfide the appropriately substituted sulfide.

COOCH-S-COR Example R R CH CH -Continued Example R1 R2 R3 X 52 H CH N-N S 04- 1| -s-C N NHCONH2 53 Ulcrl- (2H5 c n N-- N coon N 54 CH cu NN h II 3 3 I I ll 5 -s-c C-CH3 What is claimed is: l. A compound of the formula COOCl-l- S-COR wherein R is thienylmethyl or thienylmethyl bearing on the a-carbon hydroxy, amino, carboxy or ureido; R is hydrogen or lower alkyl; R;, is lower alkyl; X is hydrogen, lower alkanoyloxy, lower alkylthio, thiadiazolylthio, (lower alkyl)thiadiazolylthio, tetrazolylthio or (lower alkyl)tetrazolylthio, and acid addition salts of the basic members thereof.

2. A compound as in claim 1 wherein R is thienylmethyl or thienylmethyl bearing on the a-carbon amino or ureido; R is hydrogen or methyl; R is methyl; and X is hydrogen, lower alkanoyloxy, 1,3,4-thiadiazolylthio, S-methyl-1,3,4-thiadiazol-5-ylthio or S-methyltetrazol-l -ylthio.

3. A compound as in claim 1 wherein R is thienylmethyl bearing on the a-carbon amino or ureido.

4. A compound as in claim 1 wherein R is thienylmethyl.

5. A compound as in claim 1 wherein R is hydrogen and R is lower alkyl.

6. A compound as in claim 1 wherein R is a-amino- 3O thienylmethyl.

7. A compound as in claim 1 wherein R is a-ureidothienylmethyl.

8. A compound as in claim 1 wherein X is acetoxy.

9. A compound as in claim 1 wherein X is S-methyll ,3 ,4-thiadiazol-5-ylthio.

10. A compound as in claim 1 wherein X is S-methyltetrazoll -ylthio.

11. A compound as in claim 1 wherein R is a-aminothienylmethyl, R is hydrogen, R is methyl and X is acetoxy.

12. A compound as in claim 1 wherein R is a-ureidothienylmethyl, R is hydrogen, R is methyl and X is acetoxy.

13. A compound as in claim 1 wherein R is a-ureidothienylmethyl, R is hydrogen, R is methyl and X is (lower alkyl)thiadiazolylthio.

14. A compound as in claim 1 wherein R is a-ureidothienylmethyl, R is hydrogen, R is methyl and X is (lower alkyl)tetrazolylthio.

15. A compound as in claim 13 wherein X is S-methyl- 1 ,3 ,4-thiadiazol-5-ylthio.

16. A compound as in claim 15 wherein X is 5- methyltetrazoll-ylthio. 

1. A COMPOUND OF THE FORMULA
 2. A compound as in claim 1 wherein R1 is thienylmethyl or thienylmethyl bearing on the Alpha -carbon amino or ureido; R2 is hydrogen or methyl; R3 is methyl; and X is hydrogen, lower alkanoyloxy, 1,3,4-thiadiazolylthio, 5-methyl-1,3,4-thiadiazol-5-ylthio or 5-methyltetrazol-1-ylthio.
 3. A compound as in claim 1 wherein R1 is thienylmethyl bearing on the Alpha -carbon amino or ureido.
 4. A compound as in claim 1 wherein R1 is thienylmethyl.
 5. A compound as in claim 1 wherein R2 is hydrogen and R3 is lower alkyl.
 6. A compound as in claim 1 wherein R1 is Alpha -aminothienylmethyl.
 7. A compound as in claim 1 wherein R1 is Alpha -ureidothienylmethyl.
 8. A compound as in claim 1 wherein X is acetoxy.
 9. A compound as in claim 1 wherein X is 5-methyl-1,3,4-thiadiazol-5-ylthio.
 10. A compound as in claim 1 wherein X is 5-methyltetrazol-1-ylthio.
 11. A compound as in claim 1 wherein R1 is Alpha -aminothienylmethyl, R2 is hydrogen, R3 is methyl and X is acetoxy.
 12. A compound as in claim 1 wherein R1 is Alpha -ureidothienylmethyl, R2 is hydrogen, R3 is methyl and X is acetoxy.
 13. A compound as in claim 1 wherein R1 is Alpha -ureidothienylmethyl, R2 is hydrogen, R3 is methyl and X is (lower alkyl)thiadiazolylthio.
 14. A compound as in claim 1 wherein R1 is Alpha -ureidothienylmethyl, R2 is hydrogen, R3 is methyl and X is (lower alkyl)tetrazolylthio.
 15. A compound as in claim 13 wherein X is 5-methyl-1,3,4-thiadiazol-5-ylthio.
 16. A compound as in claim 15 wherein X is 5-methyltetrazol-1-ylthio. 